Nectin stabilization at adherens junctions is counteracted by Rab5a-dependent endocytosis

TY - JOUR

T1 - Nectin stabilization at adherens junctions is counteracted by Rab5a-dependent endocytosis

AU - Cervero, Pasquale

AU - Vrenken, Kirsten

AU - Klose, Matthias

AU - Rehm, Kerstin

AU - Linder, Stefan

N1 - Copyright © 2021 The Authors. Published by Elsevier GmbH.. All rights reserved.

PY - 2021/11/27

Y1 - 2021/11/27

N2 - Cell-cell junctions undergo constant remodeling, which is crucial for the control of vascular integrity. Indeed, transport of junctional components such as cadherins is understood in increasing depth. However, little is known about the respective pathways regulating localization of nectin at cell-cell junctions. Here, we performed an siRNA-based screen of vesicle regulators of the RabGTPase family, leading to the identification of a novel role for Rab5a in the endocytosis nectin-2 at adherens junctions of primary human endothelial cells (HUVEC). Confocal microscopy experiments revealed disordered nectin-2 localization at adherens junctions upon Rab5a depletion. In addition, internalized nectin-2 was shown to prominently localize to Rab5a-positive vesicles in both fixed and living cells. As shown previously, nectin-2 stabilization at junctions is achieved via drebrin-dependent coupling to the subcortical actin cytoskeleton. Consistently, depletion of drebrin in this study leads to enhanced internalization of nectin-2 from junctions. Strikingly, simultaneous silencing of Rab5a and drebrin restored the junctional localization of nectin-2, pointing to Rab5a as counteracting the drebrin-dependent stabilization of nectin-2 at adherens junctions. This mechanism could be further validated by transendothelial resistance measurements. Collectively, our results identify Rab5a as a key player in the endocytosis of nectin-2 and thus in the regulation of adherens junction integrity in primary human endothelial cells.

AB - Cell-cell junctions undergo constant remodeling, which is crucial for the control of vascular integrity. Indeed, transport of junctional components such as cadherins is understood in increasing depth. However, little is known about the respective pathways regulating localization of nectin at cell-cell junctions. Here, we performed an siRNA-based screen of vesicle regulators of the RabGTPase family, leading to the identification of a novel role for Rab5a in the endocytosis nectin-2 at adherens junctions of primary human endothelial cells (HUVEC). Confocal microscopy experiments revealed disordered nectin-2 localization at adherens junctions upon Rab5a depletion. In addition, internalized nectin-2 was shown to prominently localize to Rab5a-positive vesicles in both fixed and living cells. As shown previously, nectin-2 stabilization at junctions is achieved via drebrin-dependent coupling to the subcortical actin cytoskeleton. Consistently, depletion of drebrin in this study leads to enhanced internalization of nectin-2 from junctions. Strikingly, simultaneous silencing of Rab5a and drebrin restored the junctional localization of nectin-2, pointing to Rab5a as counteracting the drebrin-dependent stabilization of nectin-2 at adherens junctions. This mechanism could be further validated by transendothelial resistance measurements. Collectively, our results identify Rab5a as a key player in the endocytosis of nectin-2 and thus in the regulation of adherens junction integrity in primary human endothelial cells.

KW - Adherens Junctions

KW - Cadherins

KW - Endocytosis

KW - Endothelial Cells

KW - Humans

KW - Nectins

KW - rab5 GTP-Binding Proteins

U2 - 10.1016/j.ejcb.2021.151184

DO - 10.1016/j.ejcb.2021.151184

M3 - SCORING: Journal article

C2 - 34826799

VL - 100

JO - EUR J CELL BIOL

JF - EUR J CELL BIOL

SN - 0171-9335

IS - 7-8

M1 - 151184

ER -